Varietal and Spatiotemporal Bearings on Watermelon (Citrullus lanatus (Thunb.) Mansf.) Production in Calabar, Nigeria

Purpose: An empirical study was conducted in Calabar, Nigeria, from August to November 2019 to determine how planting dates and varieties affect rainfed watermelon (Citrullus lanatus ((Thunb.) Mansf.) growth and yield. Calabar holds the potential to support watermelon cultivation, but detailed information on its agronomic requirements is lacking in this area.Research Method: The experimental conditions included three planting dates (7 August, 27 August, and 16 September 2019) and four watermelon varieties (Koloss, Sugar Baby, Kaolack, and Heracles). The treatment combinations were organised in split-plots and placed into a randomised complete block design, with three replications.Findings and Values: All the watermelons planted on August 27 performed better than those planted on August 7 and September 16. The main vine length, number of leaves, number of branches, leaf area index, relative growth rate, and net assimilation rate showed that watermelon planted on August 27 performed best. A significant increase (P < 0.05) in fruit yield, weight, girth, length, sugar content, and number of fruits was observed on August 27 planting date compared to August 7 and September 16 planting dates. The August 27 planting date yielded 77.29 and 129.39 more fruit than August 7 and September 16, respectively. Heracles and Koloss yielded more fruit per hectare than the others. Fruit yield was ranked as follows: Heracles > Koloss > Kaolack > Sugar Baby. Heracles and the planting date of August 27 had a significant effect on fruit production. The production cost and economic returns analysis showed that August 27 was the best time to plant Heracles watermelon in Calabar.